Testing the validity of ensemble descriptions of intrinsically disordered proteins

Understanding biological function in the profusion of proteins containing significant levels of intrinsic disorder depends on how accurately we can describe their conformational behavior (1). Recently, Wang et al. used molecular dynamics (MD) techniques to study the molecular recognition element of the C-terminal domain of the measles virus nucleoprotein (MeV-NTAIL), an example of this enigmatic family of intrinsically disordered proteins (IDPs) (2). In justifying their approach, the authors state that “in general, it is not feasible to characterize IDPs by an ensemble averaged method due to the underlying structural heterogeneity.” Although the potential advantages of restraint-free MD in terms of dynamic time scales are evident, numerous developments in the field also exploit ensemble-averaged NMR data to derive molecular descriptions of IDPs.